My first electric keg still with thump keg

[MooseKnuckle]

I have been distilling since somewhere near Christmas, love the hobby, but was a little disappointed with the amount of product you get from a small still and recommended wash abv and such for the best taste, and very disappointed with the performance of my 1300w induction cooker on a 7.5 gal pot with a thump.

I recently decided to up the size a little and make things a hell of a lot easier and quicker to run. I have purchased 2 kegs, a 50L and a 30L. I wanted to go 58.6 and 20-30L but these were readily available they basically jumped in my lap so what the hell.

So after a whole lot of thought and different ideas I decided on an electric setup with a 5500w element, SCR controller for simplicity (10000w so it should be more than enough headroom to remain reliable), modular design where I can make any head I want and simply clamp it on, or even add a second boiler for steam heating down the road if I want (could do it with the thump but it's just over half the size) and I was thinking about trying out reflux down the road so should be easy enough when I get to that point. I wanted a simple small still when I started so I built one from a 7.5 gal stock pot with a 2 gal stock pot for a thump and a 24" leibig condenser.

However the issues soon arised as I started to use the thing. Not enough heat, not big enough to do a run I would call a decent size, and if I was to do multiple runs I would need to take a week off work. It needs to be fully disassembled between batches, as it is simply a stock pot with flour paste to seal everything all up and union joints to attach pipes together. While I was pretty happy with the little thing for a few reasons, my first still, nice design, everything came apart and fit inside the main pot with the head upside down and inside there too, other than the condenser which obviously wouldn't fit, the main issue was the time it took to make a batch and the ridiculous efforts it would take to do multiple runs. I had to preheat on the stovetop to get it up to a nice heat then carry it downstairs to my distilling (laundry) room, then slap it all together, run it and tear it down, we're talking probably a good 8 hours. My best run was rum which yielded about a gallon of very good tasting rum but the process took all day and then I had to clean up the next day. Basically you are looking at a $3-400 gallon of rum lol.

All these minor issues led me to put a little more thought into my next still and the main thing I wanted was a strong element and the ability to drain and refill without a full disassembly. But also the ability to adapt it to any type of still I might want in the future, so the obvious choice was the keg setup, and a lot of research on here pointed me in the proper direction. What I have now is a very nice still that I could do a single batch or 10 batches all in a row, and a hell of a lot faster than my first.

While I don't knock anyone for going easy on their first build, wetting their feet a little before they jump in, I definitely recommend a lot of reading a lot of thought on what you want to make with it, and whether you think you're going to need it or not (you WILL want it after a few runs), the ability to drain and refill is very very very important. While I did do a lot of research myself even before the first one, I did have this misconception in my head that a small, single run would be enough to satisfy me, and I had a pretty high expectation of what I would get out of it and how long it would take, and I didn't think I would ever need to go so far as to drain, refill, and do a second run without tearing it all apart. I was wrong lol.

Anyway, this is my new build, got some cleaning up to do on the solder (I intentionally put a little extra and let it drip down as there was a small pinhole leak or two on my first and didn't want to have that again, figure it's easier to sand off a little extra than have to resolder, do another cleaning run, another sacrificial run, then try again. Welds, well I was experimenting with stainless for the first time, paranoid about warping my fittings and having to wait for new ones, I chose to spot weld all the way around and was left with an ugly, but sealed, bead on all my fittings (I had another post, passivation of stainless welds, on that because of the welding gas I had on hand and thanks to all who contributed). I am up to the point where I need to set up the electrical aspect, do a full leak test of the whole assembly, and do my cleaning runs and get to running some whisky mash and rum wash I've got ready to go.

So here's my rig. Also decided to build a parrot with some extra stuff I had.

[still_stirrin]

Whew...tough read. But I understand your excitement.

Your experience underlines the "buy once, cry once" philosophy. Initial build was easy, but not well planned, resulting in poor performance. The latter build involved more knowledge of the processes and tools needed. Keeping costs down on the first build meant you quickly outgrew that still for the more "mature" design.

Kudos.

Be safe, be responsible, and be discrete.
ss

[MooseKnuckle]

Yeah I'm not the greatest with writing these things I basically get on a train of thought and yammer on forever lol. I'm not writing any books don't worry. Anyway not sure what the hell is going with these pics, they are upright when I load them and sideways when they post.... Heres a better pic for the overflow from the thump back to the boiler, I figured if I put it above the max fill of the main boiler on my thump side, and well below where the liquid would be on the boiler side, then it should function as needed without the use of a P trap, while possibly sending a small amount of vapour up that tube, I figure it would be very minimal and nothing to worry about. If anything a tiny amount of extra flavour wouldn't hurt anyway. One pic is before I cut it and put a union in, just getting everything lined up.

[bearriver]

Nice looking rig. The wall of text is fine, but it needs some spaces. It helps with eye strain.

I've been thinking about thumpers more lately, now that we got all these folks mashing and stripping with steam.

[MooseKnuckle]

There I threw in some spaces, and you're right. Even reading through my own text to find where to throw the spaces was a strain on the eyes.

[bearriver]

I tend to agree with your rational. I used Rad's calculators and punched in numbers until my needs were met, then got to building based off of those dimensions.

Too often I see people build a column or boiler that does not suit their needs, just to be replaced for a larger one down the road.

[crazy]

MooseKnuckle I very much enjoy reading about your build journey ! It looks like you have learned soo much from the time you started till now .
It appears you have well planned and laid out this upgrade and it looks fantastic ! In my humble opinion I would put the p-trap in between the boiler & thump . As any vapor traveling through the return line will be defeating the purpose of the thumper.
I look forward to hearing how she runs.

[MooseKnuckle]

So you believe that with a 1" line from boiler to thump, with all the surface area of the main boiler feeding vapour to it, that the 1/2" line with only the surface area of the inside of that 1/2" line would feed enough vapour to make a real difference? I'm not criticizing at all, just trying to make sense of it, as my belief was that the very small amount of surface area inside that pipe would feed a very insignificant amount of vapour through that line.

And even with a P trap, it is still going to have some movement of fluid, and it will still be heated, so would it really reduce the amount of vapour being sent up the pipe by a noticeable amount? Just thinking out loud...

[MooseKnuckle]

It is below the liquid level of the main boiler so I figured that it would kind of act the same as a P trap just by being down in the liquid anyway. My intial design was going to be a thump above the main boiler, and a drain back down into the top of the boiler, which would definitely need a P trap, as it would be in the vapour path and would simply blow vapour through. If and when the thumper filled to that max level, it would fill the P trap and begin to function as needed. This sounded like a pain in the ass to me, as even if I filled the Ptrap first, it may boil off and become useless half way through the run, who knows.

So my stumbling upon a smaller keg that was actually taller than the big one meant that I could put them side by side, run from a high point in the thump to a spot below the liquid in the main boiler, and eliminate the need for a Ptrap. If I'm incorrect in assuming I don't need a P trap, then I welcome that advice as it's pretty easy to go out and solder that up before I do my cleaning runs. I'd just like to know for sure that it is actually going to make a real difference.

[bearriver]

The thumper overflow drain looks fine to me as it is. The boiler charge will create a vapor lock, forcing all the vapor in the boiler to go out through the diffuser in the thumper.

[crazy]

So you believe that with a 1" line from boiler to thump, with all the surface area of the main boiler feeding vapour to it, that the 1/2" line with only the surface area of the inside of that 1/2" line would feed enough vapour to make a real difference? I'm not criticizing at all, just trying to make sense of it, as my belief was that the very small amount of surface area inside that pipe would feed a very insignificant amount of vapour through that line.

And even with a P trap, it is still going to have some movement of fluid, and it will still be heated, so would it really reduce the amount of vapour being sent up the pipe by a noticeable amount? Just thinking out loud...

I think the vapor will take the path of least resistance , The feed will be covered with fluid in the bottom of the thumper , the return line won't be covered in the thumper , My thoughts is without a trap or something the vapor will travel the least restrictive path . It's just my opinion as I'm not an engineer or anything. Try it , see how you like it , it's an easy change if you want to try a trap later.
On another note , in another thread you seem worried about the drain if you run grains in the thumper ? On my 15.5 gallon thumper I got financially embarrassed and didn't even put a drain in the thumper , I turn it upside down after a run & insert a water hose to flush it out , works a treat with no problem.

[MooseKnuckle]

Also a good point. Less resistance may outweigh the difference in surface area. Wasn't even thinking about that part of the equation. But it may not be an issue, as most of the vapour SHOULD be pushing off the larger surface area of the main boiler and I would think that the least resistance would be the 1" tube into the thump. Most of that pressure would be inside the boiler above the liquid, a small amount in the overflow, but to defeat the overflow, it would have to push the liquid down far enough to come out that pipe. Again just thinking out loud, but when you really put some thought into it, I think if it was to become an issue, it may only be after the height of liquid in the thump is above the level of the boiler, and before it reaches the point of dumping back down the overflow.

It may never even reach that level anyway, as this thump is more than half the size of the boiler. I put the overflow in as a precaution because with my 7.5 gal boiler and 2 gal thump on the first one, I had one batch where it actually filled up the thump, somehow some of my flour paste fell into the liquid, came up the pipe into my condenser, started building pressure which I counteracted by seriously clamping down the lids of both, and it eventually shot out the end like a little snot cannon, followed by a surge of liquid.

This is something that may never be an issue with the design of the new one, and I certainly wont have any flour paste in there to clog anything anyway, but the issue of sending liquid up the condenser is just as annoying and wanted to make sure that instead of probably not happening, it will NEVER happen. Valid point on the path of least resistance, but it may or may not ever get to that point, so weighing the advice from both of you, I'd say I'm going to try it as is and see how it goes. If it needs it, I'll add it in later. And if it needs it, I'll post that here when it happens.

[MooseKnuckle]

And, crazy, thanks on the grains in the thumper bit too. I'm glad to hear it was easy enough to clean even without a drain. Wasn't looking forward to finding another 2 1" fittings, welding them on, two new 1" ball valves, etc....

[still_stirrin]

I agree with bearriver and crazy, the vapor will follow the path of least resistance. However, the 1/2" line will flow much less vapor (1/4 as much) than the 1" line, so it'll meet more resistance when flowing.

Just the same, the thumper will "bump & thump" as the vapor pressure builds and pushes through the thumper charge. Those pressure surges will bump back through the liquid return line to the boiler, in part normalizing the pressures. How this affects the vapor product take off out of the thumper will likely reduce the mass throughput, and the corresponding product at the outlet.

It will behave somewhat like a water return loop on a water pump, where you regulate the water flow by adjusting the outlet to inlet flowrate with a valve. Only in the case of your thumper & boiler, it'll will be vapor circulating through the loop.

And IF the boiler liquid level is at, or above the thumper liquid outlet....your boiler will push the wash into the thumper through the 1/2" line, as the liquid seeks it's own level.

If your thumper fills (with liquid) to the level of the liquid return outlet, you'll probably be out of wash in the boiler already. It is not likely that the return line will ever be full of liquid.
ss

[still_stirrin]

Another concern for the set up is the large surface areas of the piping and the thumper. Those will conduct heat out of the vapors and will cause condensation.

I would suggest to insulate all of the thumper to help retain as much of the heat as possible. Also, the piping from the boiler to the thumper should be insulated to keep it hot once the boiler is producing.

Insulating your boiler will also help with the power efficiency and help you get to temperature quicker...and maintain steady heat inputs (temperatures) better.
ss

[MooseKnuckle]

Is it necessary that it holds household plumbing pressure or is that overkill? I'm having a hell of time sealing it up perfectly, fix one hole and theres another where that bead meets the other... Just wondering if I'm being too picky or I should keep going

[MooseKnuckle]

I backpurged with welding gas, and when I close one hole after welding, and open the next it pops so it is definitely holding a fair amount, but when I hook up the hose and turn it on with it all sealed up, I cant seem to get rid of a few pin holes on each fitting. I did have success with the element hole where I actually soldered over the weld and sealed it up perfect but the rest wouldn't take the solder for some reason and have very very small pin holes every time I reweld

[Danespirit]

Have you tried to go a little backwards on the part already welded , before turning off the arc..?
If you can't get the solder to stick, trying to solder over the weld, use a Dremel or similar to carve out the pinhole, flux it and retry.
Sometimes there are minor impuritys that are the cause of trouble...it could be worth a try..
You made a very fine still there MooseKnuckle...
Edit: It's not neccessary to pressuretest a still (you would go on 8-10 Bar), but it should hold a common household waterpressure to ensure it won't leak over time.

[MooseKnuckle]

I'm honestly considering getting two new kegs and starting over. I think the issue may be the oxygen in the gas, or possibly the cutting oil wasn't cleaned off perfectly before welding, either way it just feels like something isn't right and I'm going to have more weld seam than keg if I keep trying to seal holes like this. The solder just bounced off entirely leading to me to believe that some kind of oil is present, and when I went back to welding, no mater how solid it looked it was leaking when I hooked it up to the hose.

I have some extra fittings I ordered because they took so long and I found a supplier near my house for a decent price before they came. I would much prefer a new keg with a nice clean weld especially when it comes to passivating afterwards. I have about 800 psi left in my tank so maybe it's best I just kill the tank and get a helium based trimix or something, I hear it's decent for steel anyway just crazy expensive compared to argon/c02, but the cost is less than having both gasses I'm sure...

[Danespirit]

If you TIG or MIG weld, a Argon/CO2 mix should be sufficient, there is no need for a expensive blendgas with Helium.
As for welding, it takes a lot of oil/grease for it to spoil the job.
Anyhow...you could be on right track with Oxygen contacting the weldspot.
Have you checked the path your shieldgas takes?
There could be a obsticle or a gasket leaking...on a TIG welder the screen inside the torch might have become stuck with dirt.
Soldering is a different ballgame, a tiny amount of grease or oil will cause the flux to run around it. The result is solder failing to "wick" into the joint.
Buying new kegs might be to rush it. I would definatly try to grind the whole weld down, even use a grindingpin on a Dremel to get all the way into every edge and corner.
Then weld it up again. I think soldering is out of the game by now...it takes a clinical clean surface and tight fitting material to get a good job done.
How are your settings on the welder?

[MooseKnuckle]

it's a Hobart handler 140. 110v but a damn good 110 volt I made myself a nice winch bumper for my last truck with it and it performed amazingly on 1/8" sheet and a 2x6x1/4" C channel (quite thick in the corners) and a nice piece of 1/2" I used for some brackets as well. Like butter. I used it on 2 and 3 voltage settings (it has only 4 settings) and between 30-50 on the wire speed. The last time I used it on 4 I was afraid of blowing holes in it the first time. Not sure what the actual volt setting are as they are only labelled as 1-4. The oxygen issue I was referring to is more about the fact that my gas contains 2% oxygen. 86%argon, 12%c02, 2%oxygen. I believe I backpurged more than enough to fill it, probably wasted a fair amount of gas but better safe than sorry, taped all holes shut except the one I was welding at the time. it would take a fair amounf of grinding to bring it back down at this point as the last time I tried, I basically kept putting welds where I had holes when testing. One thing I just remembered as well was that even as I was drilling the holes in the keg itself in the beginning, the cutting oil I used didn't even seem to sit properly in some places, it just seemed to run right off and didn't seem to lubricate well, so I used a fair amount. I did clean it off before welding, but considering that it seemed like something was keeping even the oil from sitting on the steel, this is why I'm beginning to wonder if it isn't worth just getting new kegs. the only fitting I don't have another of is the 1.5" triclamp ferrule and that is cheap enough, other than the cost of 2 new kegs and possibly filling my tank again. Even if I didn't get a stainless specific gas, I would say something with NO oxygen may be better than what I have.

[MooseKnuckle]

I post these simply to show that I am not stranger to welding, or building anything in general lol There must be an issue with something that is simply not allowing me to get a good weld.

[MooseKnuckle]

Well, crazy, it seems you were somewhat right about the thump overflow, but not exactly as you described.

When I heated up some citric acid and water in her, it basically got to boil, then the steam pushed the liquid through the overflow and into the thump until it was full and dumped it out the condenser. A simple P trap would not fix this, but I believe that if I make a very deep P trap, lower than the bottom of my thump tube, it should stop this. It is simply that the thump tube goes lower than the overflow drain and it's easier to push the liquid through there than to push the steam through where I want it.

Simple fix hopefully, going to try it out tomorrow and hopefully that's the ticket, I don't see why it wouldn't work. If the thump was higher than the boiler, wouldn't be a problem. I basically got the idea from the thump tower or hillbilly flute type design, and didn't take into account the fact that my boiler and thump are side by side.

Oh well... Going to cut the thump downtube slightly shorter, probably cut slots into it rather than drill holes again, and then make that overflow dip lower than the bottom of it. Then it's time for some cleaning runs and hopefully running 16 gallons of rum wash and another 16 gallons of Sour mash through her if not all tomorrow than hopefully all on the weekend....

[MooseKnuckle]

No idea what is going on, even with a "Ptrap". Even though it doesn't need a Ptrap, I made one simply to bring the level below that of the thump downtube. It still just dumps water into the thump and fills it up until it comes through the condenser.

It doesn't even heat the 1" pipe going from the boiler to the thump, so it is simply pushing the other way instead.

[Danespirit]

How much do you fill in your boiler?
Archimedes law says liquidlevel will be even in two corresponding vessels.
I am inclined to say the liquid runs from the boiler into the thumper, caused to it's own pressure..even with that P trap.

Edit: With a thumper this size, i can't see the need for a overflow drain at all.
To get you going, a quick solution would be to cap both in and out on the boiler and thumper.
It should easy run without overflow.

[MooseKnuckle]

Well it doesn't level according to Archimedes law lol The pressure created from boiling simply pushes the liquid out the overflow, and out the top of the pipes to the condenser. I would have thought that it would be easier for vapour to flow through the thump tube than to push liquid into the thump as it is now higher than the lowest point on the overflow, but apparently that is not the case.

As for capping the holes, I will do that when I run Rum (probably) but for whiskey I wanted the overflow so I can put the wet grains in the thump and the clear(ish) wash in the boiler and basically distill on the grain for the stripping run. Since the thump will have a fair amount of grain in it, I figure it is just safer to have an overflow so that I can put a good amount of liquid in there with the grains to start off so that it isn't thumping through basically an oatmeal consistency of sludge.

What I have since decided is that I'm going to take the part of my overflow that screws into the main boiler, insert a piece of 1/2" coil I had on hand, solder it and turn it up towards the top of the boiler, thus eliminating the ability to pump liquid into the thump. It may pump a small amount of liquid in there to begin with but after that it should just stop and send the vapour up the tube where it belongs.... I suppose this would be the equivalent of having an overflow with a Ptrap that joins to the boiler above the liquid line (which is what I didn't want for fear of it boiling away and becoming a vapour tube) but whatever, going to see how that works. If it doesn't work.... Well we'll simply plug it up for everything and maybe distilling on the grain wont work so well... Who knows the grains may clog the overflow and render it useless when I try it out anyway.

[MooseKnuckle]

Oh and I suppose I didn't answer your question. I haven't done a run yet, I figured I would probably do something near 10 gallons in the boiler and the other 4-5 (with grains) in the thump when doing a whiskey, and haven't really put a lot of thought into the rum yet. Probably try one with wash in both just like the whiskey but no grains obviously (I use 15 gallon fermenters) and see how that works. That would be the stripping runs, and while I may or may not do spirit runs with rum, for the whiskey I would build up the low wines and then fill the boiler with that and throw a small amount of it into the thump or simply water. Probably try both and see which I like more. What I did this time was fill the boiler until it started pouring into the thump, then let it go a bit longer to cover the downtube (this was all water with a bit of vinegar). I just felt where it was warming the sides of the thump to judge where the level was at.

I suppose when you let the two equalize pressure between them, it may simply not allow the thumper to do it's job, but then how the hell does a thump tower work, or why does this exact same thing work fine when the thumper is mounted above the boiler... I was honestly thinking about redoing some pipes and mounting the thump higher, but then if I went through all that work and it didn't work again I think I'd be a little pissed lol Gonna try my simple little up-turned pipe and see how it goes, if that doesn't work than no overflow for now I just wanna get to making some spirits, and later I can make something for distilling the stripping run of whiskey on the grain.

[MooseKnuckle]

Still didn't work. So I capped them, and that is that. Running like a dream on the cleaning runs and I'm going to do some hooch tomorrow, we'll see if the thumper size is good enough to do grains in there without any trouble on my first big whiskey stripping run and the Rum should be absolutely no problem whatsoever. Thanks fro the advice to everyone who chipped in anyway, wish I could have had an overflow but whatever I'll live without it and figure something else out later for the whiskey stripping runs. Maybe another full sized keg as a thump or something if this one isn't good. I'd like to do a few different setups down the road anyway that I can just clamp onto this boiler.

[MooseKnuckle]

Well after some running around I only had time to do my final cleaning run, the sacrificial alcohol one.

Had about 3.5 gallons of cider smelling stuff that came in my keg and was left in a carboy for this purpose, about a liter each of rum tails and whiskey tails and threw in a bunch of water to bring it up to probably about 10 gal. 2 hrs later I've got a gallon in my jar and still going.

This thing beats the *&#$^ out of my old one by a long shot, couldn't be happier. And that's without any sort of insulation. I'm going to try insulating the boiler and if I insukate the pipe at all it's just going to be the up and over towards the thump sections. Leave everything after the horizontal run. Going to give me a lot more drink in a lot less time and leave me more time to enjoy the stuff I make lol. Cant wait to make that rum and whiskey.

Absolutely love the control. Went with the SCR controller $45 off ebay, almost instant control, make an adjustment, a second or so later you can see it.

[crazy]

Sounds cool so far ! Glad your liking it !